Newt left as lake vanishes (3)
I believe the answer is:
eft
'newt' is the definition.
(eft is a kind of newt)
'left as lake vanishes' is the wordplay.
'EFT' is hidden in amongst the letters.
But, I'm uncertain how the hidden word is indicated.
(Other definitions for eft that I've seen before include "Juvenile twenty-three Ac; rhymes with sinister" , "Small amphibian" , "Juvenile newt" , "Little creature" , "Pond creature" .)